Adjusting a parameter for a programming operation based on the temperature of a memory system

ABSTRACT

A processing device, operatively coupled with a memory device, is configured to identify a temperature related to a memory device of a plurality of memory devices; to determine, whether the temperature satisfies a threshold temperature condition; responsive to detecting that the temperature related to the memory device satisfies the threshold temperature condition, to identify an entry associated with the memory device from a plurality of entries in a data structure, wherein each entry of the plurality of entries corresponds to one of the plurality of memory devices; to determine a parameter value associated with the memory device from the entry, wherein the parameter value is for a programming operation to store data at the memory device; to adjust the parameter value associated with the memory device to generate an adjusted parameter value; and to store the adjusted parameter value in the entry of the data structure.

RELATED APPLICATIONS

This application is a continuation application of co-pending U.S. patentapplication Ser. No. 15/913,168, filed Mar. 6, 2018, which isincorporated by reference herein.

TECHNICAL FIELD

Embodiments of the disclosure relate generally to memory systems, andmore specifically, relate to adjusting a parameter for a programmingoperation based on temperature of a memory system.

BACKGROUND

A memory system can be a storage system, such as a solid-state drive(SSD), and can include one or more memory components that store data.For example, a memory system can include memory devices such asnon-volatile memory devices and volatile memory devices. The memorysystem can further include a controller that can manage each of thememory devices and allocate data to be stored at the memory devices. Ahost system can utilize the memory system and request data from thememory system. The controller can be used to retrieve data from thecorresponding memory devices and return the retrieved data to the hostsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousembodiments of the disclosure. The drawings, however, should not betaken to limit the disclosure to the specific embodiments, but are forexplanation and understanding only.

FIG. 1 illustrates an example computing environment that includes astorage system in accordance with some embodiments of the presentdisclosure.

FIG. 2 illustrates a storage system that adjusts a parameter for aprogramming operation based on a temperature in accordance with someembodiments of the present disclosure.

FIG. 3 illustrates another view of the storage system in accordance withsome embodiments of the present disclosure.

FIG. 4 is a flow diagram of an example method to adjust a parameter fora programming operation based on a temperature in accordance with someembodiments of the present disclosure.

FIG. 5 is a flow diagram of an example method to update a parameter fora programming operation based on a temperature in accordance with someembodiments of the present disclosure.

FIG. 6 is a block diagram of an example computer system in whichimplementations of the present disclosure can operate.

DETAILED DESCRIPTION

Aspects of the present disclosure are directed to adjusting a parameterfor a programming operation based on a temperature of a memory system.An example of a memory system is a storage system, such as a solid-statedrive (SSD). In some embodiments, the memory system is a hybridmemory/storage system. A storage system is used as an example of amemory system throughout this document. In general, a host system canutilize a storage system that includes one or more memory devices. Thememory devices can include non-volatile memory devices, such as, forexample, negative-and (NAND). The host system can provide data to bestored at the storage system. The data can be stored at and retrievedfrom memory devices within the storage system. The memory devices of thestorage system can include memory cells that are used to store data fromthe host system.

Each memory cell can store data values as a threshold voltage for thatparticular memory cell. In one example, the memory devices of thestorage system can include a single-level-cell (SLC) memory where eachmemory cell of the SLC memory can be programmed with a single bit ofdata. When storing one bit of data in the SLC memory, a range ofpossible threshold voltages of a memory cell is divided into two ranges.For example, the two ranges can include a first threshold voltage rangethat corresponds to the logical data value “1” and a second thresholdvoltage range that corresponds to the logical data value “0.”

Some storage systems can include higher density memory devices such asmulti-level-cell (MLC) memory that is programmed by storing 2 bits permemory cell, 3 bits per memory cell, 4 bits per memory cell, or morebits per memory cell. Data can be stored at an MLC memory based on atotal threshold voltage range that is divided into distinct thresholdvoltage ranges for the memory cells. Each distinct threshold voltagerange corresponds to a predetermined value for the data stored at thememory cell.

In the case of storing multiple bits of data at a single memory cell,the total threshold voltage range for the memory cell is divided intothe distinct threshold voltage ranges corresponding to the number oflevels of data (e.g., possible values of the data). For example, if fourlevels of data are stored at a single memory cell, then the totalthreshold voltage range for the single memory cell can be divided intofour threshold voltage ranges that are separately assigned to thelogical data values “11”, “10”, “01”, and “00.”

Conventional storage systems can store multiple bits of data in a singlememory cell by mapping sequences of bits of the data to the differentthreshold voltage ranges of the memory cell. For example, a particularlogical data value ‘11’) can be assigned to a threshold voltage rangeand another logical data value (e.g., ‘10’) can be assigned to anotherthreshold voltage range of the memory cell. The data can be stored intothe memory cell by using a programming operation that applies a sequenceof programming pulses to the memory cell. The sequence of programmingpulses can be applied to the memory cell until a voltage level within acorresponding threshold voltage range has been reached at the memorycell. After the memory, cell has been programmed, data can be read fromthe memory cell by applying a read threshold voltage to the memory cellat the corresponding threshold voltage range and translating theprogrammed voltage level at the memory cell.

The storage system can be operated in an environment with varyingtemperature extremes (e.g., between 0 to 70 degrees Celsius (° C.)). Insuch cases, the integrity of the data stored in the memory cells can beadversely affected. For example, the voltage level associated with amemory cell can shift from being detected at a particular read thresholdvoltage as the temperature of the storage system changes. This resultsin increased raw bit error rate (RBER) which can be beyond the errorcorrection capability of the underlying error correction code (ECC).This can be problematic when translating voltages into data values thatcorrespond to the various threshold voltage (Vt) ranges of the memorycell. As the temperature decreases to a certain level (e.g., to 0° C.),threshold voltage distributions widen and shifts resulting in increasedRBER and this consequently results in an incorrect voltage levelassociation with the memory cells.

Embodiments of the disclosure address the above and other deficienciesby reducing a programming step size (e.g., the amount that the voltagevalue is increased between each of the successive programming pulses)from a default programming step size when the temperature of the storagesystem has dropped below a threshold level. The programming step size isa parameter used to perform a programming operation. For example, thestorage system can program data to the memory cells by using a sequenceof programming pulses using a particular programming step size. Thestorage system can use a default programming step size (e.g., an initialvoltage value) when the storage system is at an initial temperaturerange (e.g., an average room temperature). Smaller programming step sizeresults in finer placement of voltage distributions (i.e., tighter Vtdistributions) and hence lower RBER.

When the storage system detects that a lower temperature range ispresent, the storage system can reduce the speed of the programming ofmemory cells by reducing the programming step size from its defaultvalue to an updated value. The updated value can specify a lowerprogramming step size (e.g., a smaller increase in the voltage valuebetween successive programming pulses). This allows the storage systemto reduce the effects of an extreme temperature change by slowing downthe programming of the memory cells resulting in tighter Vtdistributions. When the storage system returns to the initialtemperature range, the storage system speeds up programming of thememory cells by reverting the programming step size from the updatedvalue to the initial value.

In some implementations, the storage system can adjust the programmingstep size when the temperature decreases further based on acharacterization (e.g., error rate) of storage system. For example, bydecreasing the programming step size from the default value to theupdated value, the number of programming pulses to program a memory cellincreases. Because of the reduction in programming step size, the readbudget window (RWB) (which represents the sum of edge margins betweenadjustment threshold states) can increase, e.g., an increase in marginbetween different threshold voltage ranges, which means the storagesystem encounters fewer read errors. In this way, the storage systemgains back the some or the entire margin in the RWB that is lost whenthe temperature drops to a certain level (e.g., to 0° C.). When theprogramming step size is reduced, a programming time to program a memorycell increases as additional programming pulses are used to program thememory cell. As a result of programming performance loss, the smallerstep size is only used when temperature goes below a threshold. Ifprogramming step size is reduced too much, due to increase inprogramming time some low voltage cells might experience increasedprogram disturb resulting in higher RBER. Therefore, caution needs to beexercised while reducing programming step size.

FIG. 1 illustrates an example computing environment 100 that includes amemory system in accordance with some implementations of the presentdisclosure. The memory system can include media, such as memory devices112A to 112N. The memory devices 112A to 112N can be volatile memorydevices, non-volatile memory devices, or a combination of such. In someembodiments, the memory system is a storage system (e.g., storage system110). An example of a storage system 110 is a solid-state drive (SSD).In general, the computing environment 100 can include a host system 120that uses the storage system 110. In some implementations, the hostsystem 120 can write data to the storage system 110 and read data fromthe storage system 110. In some embodiments, the memory system is ahybrid memory/storage system.

The host system 120 can be a computing device such as a desktopcomputer, laptop computer, network server, mobile device, or suchcomputing device that includes a memory and a processing device. Thehost system 120 can include or be coupled to the storage system 110 sothat the host system 120 can read data from or write data to the storagesystem 110. The host system 120 can be coupled to the storage system 110via a physical host interface. As used herein, “coupled to” generallyrefers to a connection between components, which can be an indirectcommunicative connection or direct communicative connection (e.g.,without intervening components), whether wired or wireless, includingconnections such as, electrical, optical, magnetic, etc. Examples of aphysical host interface include, but are not limited to, a serialadvanced technology attachment (SATA) interface, a peripheral componentinterconnect express (PCIe) interface, universal serial bus (USB)interface, Fibre Channel, Serial Attached SCSI (SAS), etc. The physicalhost interface can be used to transmit data between the host system 120and the storage system 110. The host system 120 can further utilize anNVM Express (NVMe) interface to access the memory devices 112A to 112Nwhen the storage system 110 is coupled with the host system 120 by thePCIe interface. The physical host interface can provide an interface forpassing control, address, data, and other signals between the storagesystem 110 and the host system 120.

As shown in FIG. 1, the storage system 110 can include a controller 111and memory devices 112A to 112N. The memory devices 112A to 112N caninclude any combination of the different types of non-volatile memorydevices and/or volatile memory devices. An example of non-volatilememory devices includes a negative-and (NAND) type flash memory. Each ofthe memory devices 112A to 112N can include one or more arrays of memorycells such as single level cells (SLCs) or multi-level cells (MLCs)(e.g., triple level cells (TLCs) or quad-level cells (QLCs)). In someimplementations, a particular memory device can include both an SLCportion and a MLC portion of memory cells. Each of the memory cells canstore bits of data (e.g., data blocks) used by the host system 120.Although non-volatile memory devices such as NAND type flash memory aredescribed, the memory devices 112A to 112N can be based on any othertype of memory such as a volatile memory. In some implementations, thememory devices 112A to 112N can be, but are not limited to, randomaccess memory (RAM), read-only memory (ROM), dynamic random accessmemory (DRAM), synchronous dynamic random access memory (SDRAM), phasechange memory (PCM), magneto random access memory (MRAM), negative-or(NOR) flash memory, electrically erasable programmable read-only memory(EEPROM), and a cross-point array of non-volatile memory cells. Across-point array of non-volatile memory can perform bit storage basedon a change of bulk resistance, in conjunction with a stackablecross-gridded data access array. Additionally, in contrast to manyFlash-based memories, cross point non-volatile memory can perform awrite in-place operation, where a non-volatile memory cell can beprogrammed without the non-volatile memory cell being previously erased.Furthermore, the memory cells of the memory devices 112A to 112N can begrouped as memory pages or data blocks that can refer to a unit of thememory device used to store data.

The controller 111 can communicate with the memory devices 112A to 112Nto perform operations such as reading data, writing data, or erasingdata at the memory devices 112A to 112N and other such operations. Thecontroller 111 can include hardware such as one or more integratedcircuits and/or discrete components, a processing device, a buffermemory, software such as firmware or other instructions, or acombination thereof. In general, the controller 111 can receive commandsor operations from the host system 120 and can convert the commands oroperations into instructions or appropriate commands to achieve thedesired access to the memory devices 112A to 112N. The controller 111can be responsible for other operations such as wear levelingoperations, garbage collection operations, error detection anderror-correcting code (ECC) operations, encryption operations, cachingoperations, and address translations between a logical block address anda physical block address that are associated with the memory devices112A to 112N. The controller 111 can further include host interfacecircuitry to communicate with the host system 120 via the physical hostinterface. The host interface circuitry can convert the commandsreceived from the host system into command instructions to access thememory devices 112A to 112N as well as convert responses associated withthe memory devices 112A to 112N into information for the host system120.

The storage system 110 can include a write parameter adjuster 113 (e.g.,circuitry, dedicated logic, programmable logic, firmware, etc.) toperform the operations described herein. In some embodiments, thecontroller 111 includes at least a portion of the programming component113. The write parameter adjuster 113 can be used to adjust writeparameters (e.g., programming step size) for programming data receivedfrom the host system 120 to the memory device 112A to 112N. As the datafrom the host system 120 is received to be stored at the storage system,the write parameter adjuster 113 can detect that a temperature of thecomputing environment 100 has dropped below a certain threshold level.

Upon receiving an indication of the temperature being below thethreshold level, the write parameter adjuster 113 can reduce theprogramming step size that is used to program data at the memory cellprogramming. For example, the write parameter adjuster 113 can decreasethe programming step size from a first default value to a second value.Once the operating temperature of the computing environment 100 returnsto over the threshold level, the write parameter adjuster 113 revertsback to performing the programming of data at the memory cell with theprogramming step size at the first default value. Further details withregards to the operations of the write parameter adjuster 113 aredescribed below.

The storage system 110 can also include additional circuitry orcomponents that are not illustrated. For example, the storage system 110can include a cache or buffer (e.g., DRAM) and address circuitry (e.g.,a row decoder and a column decoder) that can receive an address from thecontroller 111 and decode the address to access the memory devices 112Ato 112N.

FIG. 2 illustrates a storage system 200 to adjust a parameter based on atemperature in accordance with some embodiments of the presentdisclosure. In general, the storage system 200 can correspond to thestorage system 110 of FIG. 1. For example, the storage system 200 caninclude controller 111 of FIG. 1. In some implementations, thecontroller 111 can be configured to retrieve temperature measurementsassociated with the memory device 230. The controller 111 can beconfigured to adjust a programming step size (i.e., a parameter) forprogramming operations on the memory device 230 based on the temperaturemeasurements.

As shown, the memory device 230 can be organized into one or more blocksB1-n. The blocks B1-n each include multiple memory pages that cancorrespond to portions of the memory device 230. The size andconfiguration of the blocks B1-n can vary. For example, each of theblocks B1-n can include any number of memory pages, and each memory pagecan have an associated storage capacity for storing data.

Data can be programmed, read, and/or erased from the memory pages of theblocks B1-n. In some implementations, the memory pages can correspond toa group of memory cells that are read and/or programmed together. Thememory cells can be programmed using an iterative programming process.In this type of process, a sequence of programming pulses is applied toa group of memory cells until the desired voltage levels in the memorycells is reached. Once the memory cells have been programmed, data canbe read from the memory cells by translating the programmed voltagelevel of the memory cells.

In some implementations, the controller 111 can determine whether thestorage system 200 is operating within a certain temperature range. Forexample, the controller 111 can detect a change in temperature beyond athreshold level. Temperature information for the storage system 200 canbe obtained when programming the memory device 230 and used to adjustcertain programming operations. In response to detecting that there is achange in the temperature, the controller 111 can adjust certain writeparameters (e.g., programming step size) for programming data to thememory cells of memory device 230.

Temperature information associated with the memory device 230 can beobtained in several ways. For example, the temperature information caninclude temperature measurements T2 215 from one or more temperaturesensors 210 located in and around memory device 230 and/or temperaturemeasurements from other temperature sensors that are associated withother components of system 200 (e.g., controller 111). The controller111 can obtain temperature measurements T2 215 from the sensors 210 todetermine whether the storage system 200 is operating within apermissible temperature range T1 205. In some implementations, thetemperature sensors 210 can be configured to measure a temperature 215and to provide an indication of the measured temperature 215 to thecontroller 111. In other implementations, the temperature sensors 210can be responsive to one or more commands that can be sent by thecontroller 111, such as a command to measure temperature 215.

The controller 111 can also include temperature comparison operation 240to determine whether the storage system 200 is operating at atemperature below a threshold temperature level (e.g., at or below 0°C.). For example, the temperature comparison operation 240 can compare afirst (preset) temperature 205 associated with the memory device 230 toa current or second temperature 215 reading from the sensor 210. Thefirst temperature 205 can be a preset temperature specification for thestorage system 200. The preset temperature specification can indicate arange of optimal temperatures for the storage system 200. The secondtemperature 215 can be related to a time in which data is to beprogrammed to the memory device 230.

To compare the two temperatures, the temperature comparison operation240 can determine a difference 225 between the first temperature 205 andthe second temperature 215. The difference 225 can indicate whetherthere is a shift in the operating temperature of storage system 200. Forexample, the difference 225 can indicate a decrease in temperatureassociated with the memory device 230 that is the storage system 200(e.g., the temperature dropping from 70° C. to 0° C.). In someimplementations, the difference 225 can indicate an increase intemperature associated with the memory device 230 (e.g., the temperaturereturning from 0° C. to 70° C.).

Upon detecting a change in temperature, the controller 111 determineswhether the difference 225 satisfies a temperature threshold 224. Insome implementations, temperature threshold 224 can be represented by atemperature threshold range for adjusting the programming step size 240.For example, the temperature threshold range can include a firstthreshold that indicates a lower boundary to a first temperature range.This first temperature range can correspond to an “optimal” temperaturerange, such as typical room temperature. The temperature threshold rangecan also include a second threshold corresponding to an “extreme”temperature range of temperatures that fall below a lowest temperatureof the first temperature range.

If the temperature change satisfies temperature threshold 224, thecontroller 111 can slow down programming of data to the memory device230 by adjusting a write parameter. For example, when the change intemperature satisfies the temperature threshold 224, a size of theprogramming step used to write data to the block B1 can be decreasedfrom the first programming step size S1 to the second programming stepsize S2. To illustrate, the controller 111 can adjust the programmingstep size from a first value (e.g., the first programming step size S1)to a second value (e.g., the second programming step size S2) at leastpartially based on the temperature threshold 224.

To adjust the programming step size 240, the controller can select thesecond value from a data structure, such as a table, of programming stepsizes. For example, the difference 225 in temperature change can be usedas an index to retrieve the second value from the data structure. Thedata structure provides a level of granularity for decreasing theprogramming step size 240 as the temperature drops through several lowertemperature ranges. For example, if the temperature drops 35° C., aparticular second programming step size S2 can be selected. If thetemperature drops another 35° C., a different lower programming stepsize can be selected. In other implementations, the second programmingstep size can be stored as a fixed value to subtract from the currentprogramming step size S2 when the temperature change satisfies thetemperature threshold 224.

By decreasing the programming step size 240 from a first value (e.g.,the first programming step size S1) to a second value (e.g., the secondprogramming step size S2) for programming data to a block B1 of memorydevice 230, the number of programming steps, and thus the programmingtime can increase. Due to the smaller programming step size that is usedto program the memory cells of the memory device 230, the dataprogrammed to the block B1 can encounter reduced errors. This is becausethe smaller programming step size is a finer placement of levels whichresults in tighter Vt distributions and hence the reduced error rate. Insome situations, however, the repeated application of programming pulsesdue to the smaller programming step size can increase the error rate dueto increased programming time causing higher program disturb resultingin a higher raw-bit-error-rate (RBER).

In some implementations, the controller 111 in conjunction with thetemperature change can further determine an amount to update theprogramming step size based partially on an error rate of the memorydevice satisfying an error threshold rate. During the indicated lowtemperature operating condition when a reduced programming step size isused to program data, the controller 111 can also read datacorresponding to the block B1. The controller 111 can determine an errorcount 230 based on the read data and can compare that error count 230 tothe error rate threshold 234. If the error count 230 satisfies the errorrate threshold 234, (e.g., the block error count 230 is below the errorrate threshold 234), then the programming step size 240 can be adjustedwithout adversely impacting the memory device 230.

If the error count 230 is greater than the error rate threshold 234,then the likelihood of errors from the read data being caused by theadjustment to the programming step size can increase. Thus, theadjustment of the programming step size 240 to the second programmingstep size S2 is rejected by the controller 111 due to the impact to thememory device 230. Otherwise, the controller 111 can send the secondprogramming step size S2 to the memory device 230 for use during a nextprogramming operation to store data at the block B1.

Once the operating temperature returns to the prior temperature range(e.g., above the threshold temperature level), the controller 111 canreturn the programming step size to the initial default value S1. Forexample, the controller 111 determines whether the current temperatureT1 205 from sensor 210 is within a range that corresponds to a preferredtemperature range (e.g., approximately room temperature). As a result,the controller 111 can increase the rate of the programming of data tothe memory device 230 by adjusting the programming step size. Forexample, the controller 111 can increase the programming step size 340from the second programming step size S2 to the first programming stepsize S1. The controller 111 can then provide the programming step size240 to the memory device 230 for use during the next programming orwrite operation.

FIG. 3 illustrates another view 300 of the storage system 200 of FIG. 2in accordance with some embodiments of the present disclosure. In thisexample, the storage system 200 can include one or more dies 330, 332and 334 coupled to controller 111. A die is a small block ofsemiconducting material on which functional circuits are fabricated.Each die may include a separate memory device organized into multiplememory blocks. As shown, memory die 330 includes memory device 230 whichincludes one or more of data blocks B1-n. Although programming step sizecan be the same for all the data stored on a particular memory die, thetechniques disclosed herein can be used to dynamically program theprogramming step size for each memory die based on the temperaturechange and a characterization of the respective memory die. For example,the techniques can be used to track die-to-die variability in which eachdie starts with a different initial (or default) programming step size.Then, due to a temperature change, the programming step sizes aredecreased a fixed value from their respective default values.

To track the die-to-die variability for each die, the controller cangenerate and manage a data structure such as a data structure 350, suchas a table. The data structure 350 can include a number of entries foreach memory device where each of the entries includes informationassociated with the fields 352, 354, and 356. For example, the datastructure 350 can include a first field 352 to identity a particulardie, a second field 354 to identity an error count of the memory deviceassociated with the die, and a third field 356 to identify theprogramming step size associated with the die. During the indicated lowtemperature operation, the controller 111 can read data corresponding tothe memory device of the die and determine an error count 230 based onthe read data. Thereupon, the controller 111 can store the error count230 for that particular die in its corresponding field 354 of the datastructure 350.

Using the data structure 350, the controller 111 can adjust theprogramming step size or write parameters for each die. For example, inresponse to a change in temperature, the controller 111 can read datafrom the data structure 350 corresponding to each die. The controller111 can identify error rate 354 for the die and compare the error rate354 to the error rate threshold 234. If the error rate 354 satisfies theerror rate threshold 234, (e.g., the error rate 354 is below thethreshold 234), the controller 111 can provide the programming step sizeadjustments 340, 342, and 344 to the corresponding memory devices 230,332, and 334 for use during a next programming operation. For example,in response to an increase in temperature, the controller 111 candecrease the programming step size for die 332 a fixed value 342 and die334 a fixed value 344 from their respective default values.

FIG. 4 is a flow diagram of an example method 400 to adjust a writeparameter based on a temperature in accordance with some embodiments ofthe present disclosure. Method 400 can be performed by processing logicthat can include hardware (e.g., circuitry, dedicated logic,programmable logic, microcode, etc.), software (such as instructions runon a processing device), firmware, or a combination thereof. In oneembodiment, the write parameter adjuster 113 of a processing device(e.g., controller 111) in FIG. 1 can perform method 400. Although shownin a particular sequence or order, unless otherwise specified, the orderof the processes can be modified. Thus, the illustrated implementationsshould be understood only as examples, and the illustrated processes canbe performed in a different order, and some processes can be performedin parallel. Additionally, one or more processes can be omitted invarious embodiments. Thus, not all processes are required in everyimplementation. Other process flows are possible.

At block 402, a processing device identifies a temperature related to amemory device. For example, the temperature can be current operatingtemperature for a storage system that includes the memory device. Thetemperature can be the current operating temperature for the storagesystem at a time when data is to be programmed to the memory device ofthe storage system.

At block 404, the processing device determines whether the temperaturerelated to the memory device satisfies a threshold temperaturecondition. The temperature can satisfy the threshold temperaturecondition when the current operating temperature exceeds the thresholdtemperature condition or is below the temperature threshold condition.For example, the threshold temperature condition can specify a thresholdtemperature and the temperature related to the memory device can beconsidered to satisfy the threshold temperature condition when thetemperature related to the memory device is equal to or lower than thethreshold temperature. In some implementations, the temperature relatedto the memory device can be considered to satisfy the thresholdtemperature condition when the temperature related to the memory deviceis equal to or higher than the threshold temperature.

In some implementations, the processing device determines a differencebetween temperature and a second temperature related to programming datato the memory device. The second temperature is related to an initial orpreferred operating temperature for the storage. The processing devicecan compare the two temperatures by determining a difference between thefirst temperature and the second temperature. The difference canindicate whether there is a shift in the operating temperature of thestorage system. For example, the difference can indicate a decrease intemperature associated with the memory device and an increase intemperature associated with the memory device.

At block 406, the processing device adjusts a parameter from a firstvalue to a second value for a programming operation to store data at thememory device in response to detecting that the temperature related tothe memory device satisfies the threshold temperature condition. Theparameter of the programming operation can be the programming step sizeto program the data at the memory device. For example, the programmingstep size at the first value may increase the voltage of each successiveprogramming pulse that is to program the data by the first value. Whenthe programming step size is adjusted to the second value, then thevoltage of each successive programming pulse to program the data can beincreased by the second value. In some implementations, temperaturethreshold condition can be represented by a series of temperaturethresholds for adjusting the programming step size. For example,temperature thresholds include a first threshold that indicates a lowerboundary to a first temperature range. This first temperature range cancorrespond to an “optimal” temperature range, such as typical roomtemperature. The temperature thresholds can also include a secondthreshold that can correspond to an “extreme” temperature range oftemperatures that fall below a lowest temperature of the firsttemperature range.

FIG. 5 is a flow diagram of an example method 500 to update a parameterfor a programming operation based on a temperature in accordance withsome embodiments of the present disclosure. Method 500 can be performedby processing logic that can include hardware (e.g., circuitry,dedicated logic, programmable logic, microcode, etc.), software (such asinstructions run on a processing device), firmware, or a combinationthereof. In one embodiment, the write parameter adjuster 113 of aprocessing device (e.g., controller 111) in FIG. 1 can perform method500. Although shown in a particular sequence or order, unless otherwisespecified, the order of the processes can be modified. Thus, theillustrated implementations should be understood only as examples, andthe illustrated processes can be performed in a different order, andsome processes can be performed in parallel. Additionally, one or moreprocesses can be omitted in various embodiments. Thus, not all processesare required in every implementation. Other process flows are possible.

At block 502 a processing device receives a temperature associated witha programming operation to store data at the memory device. For example,the temperature can be received from one or more sensors associated withthe memory device. The memory device can include multi-level cells(MLCs).

At block 504, the temperature is compared related to the memory deviceto a threshold temperature condition. For example, the processing devicedetermines that the temperature related to the memory device satisfiesthe threshold temperature condition when the temperature is above orbelow a threshold temperature.

At block 506, the processing device can identify a characterization ofthe memory device. To characterize the memory device, the processingdevice can determine an error rate associated with the memory device.For example, the processing device can perform a read operation for datastored at the memory device to identity an error rate related to thememory device.

At block 508, a programming step size for the programming operation isupdated from a first value to a second value based on the comparison andthe characterization of the memory device. In this regards, the updateto the programming step size from the first value to the second value isbased on the error rate of the memory device satisfying a thresholderror rate. If the error rate satisfies the error rate threshold, theprocessing device can provide the programming step size adjustments tothe corresponding memory devices for use during a next programmingoperation.

FIG. 6 illustrates an example machine of a computer system 600 withinwhich a set of instructions, for causing the machine to perform any oneor more of the methodologies discussed herein, can be executed. Forexample, the computer system 600 can correspond to a host system (e.g.,the host system 120 of FIG. 1) that includes or utilizes a storagesystem (e.g., the storage system 110 of FIG. 1) or can be used toperform the operations of a controller (e.g., to execute an operatingsystem to perform operations corresponding to the write parameteradjuster 113 of FIG. 1). In alternative implementations, the machine canbe connected (e.g., networked) to other machines in a LAN, an intranet,an extranet, and/or the Internet. The machine can operate in thecapacity of a server or a client machine in client-server networkenvironment, as a peer machine in a peer-to-peer (or distributed)network environment, or as a server or a client machine in a cloudcomputing infrastructure or environment.

The example computer system 600 includes a processing device 602, a mainmemory 604 (e.g., read-only memory (ROM), flash memory, dynamic randomaccess memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM(RDRAM), etc.), a static memory 606 (e.g., flash memory, static randomaccess memory (SRAM), etc.), and a data storage system 618, whichcommunicate with each other via a bus 630. Processing device 602represents one or more general-purpose processing devices such as amicroprocessor, a central processing unit, or the like. Moreparticularly, the processing device can be a complex instruction setcomputing (CISC) microprocessor, reduced instruction set computing(RISC) microprocessor, very long instruction word (VLIW) microprocessor,or a processor implementing other instruction sets, or processorsimplementing a combination of instruction sets. Processing device 602can also be one or more special-purpose processing devices such as anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), a digital signal processor (DSP), network processor,or the like. The processing device 602 is configured to executeinstructions 626 for performing the operations and steps discussedherein. The computer system 600 can further include a network interfacedevice 608 to communicate over the network 620.

The data storage system 618 can include a machine-readable storagemedium 624 (also known as a computer-readable medium) on which is storedone or more sets of instructions or software 626 embodying any one ormore of the methodologies or functions described herein. Theinstructions 626 can also reside, completely or at least partially,within the main memory 604 and/or within the processing device 602during execution thereof by the computer system 600, the main memory 604and the processing device 602 also constituting machine-readable storagemedia. The machine-readable storage medium 624, data storage system 618,and/or main memory 604 can correspond to the storage system 110 of FIG.1.

In one implementation, the instructions 626 include instructions toimplement functionality corresponding to a write parameter adjuster(e.g., the write parameter adjuster 113 of FIG. 1). While themachine-readable storage medium 624 is shown in an exampleimplementation to be a single medium, the term “machine-readable storagemedium” should be taken to include a single medium or multiple mediathat store the one or more sets of instructions. The term“machine-readable storage medium” shall also be taken to include anymedium that is capable of storing or encoding a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies of the present disclosure. The term“machine-readable storage medium” shall accordingly be taken to include,but not be limited to, solid-state memories, optical media, and magneticmedia.

Some portions of the preceding detailed descriptions have been presentedin terms of algorithms and symbolic representations of operations ondata bits within a computer memory. These algorithmic descriptions andrepresentations are the ways used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of operations leading to adesired result. The operations are those requiring physicalmanipulations of physical quantities. Usually, though not necessarily,these quantities take the form of electrical or magnetic signals capableof being stored, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. The presentdisclosure can refer to the action and processes of a computer system,or similar electronic computing device, that manipulates and transformsdata represented as physical (electronic) quantities within the computersystem's registers and memories into other data similarly represented asphysical quantities within the computer system memories or registers orother such information storage systems.

The present disclosure also relates to an apparatus for performing theoperations herein. This apparatus can be specially constructed for theintended purposes, or it can include a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program can be stored in a computerreadable storage medium, such as, but not limited to, any type of diskincluding floppy disks, optical disks, CD-ROMs, and magnetic-opticaldisks, read-only memories (ROMs), random access memories (RAMs), EPROMs,EEPROMs, magnetic or optical cards, or any type of media suitable forstoring electronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems can be used with programs in accordance with the teachingsherein, or it can prove convenient to construct a more specializedapparatus to perform the method. The structure for a variety of thesesystems will appear as set forth in the description below. In addition,the present disclosure is not described with reference to any particularprogramming language. It will be appreciated that a variety ofprogramming languages can be used to implement the teachings of thedisclosure as described herein.

The present disclosure can be provided as a computer program product, orsoftware, that can include a machine-readable medium having storedthereon instructions, which can be used to program a computer system (orother electronic devices) to perform a process according to the presentdisclosure. A machine-readable medium includes any mechanism for storinginformation in a form readable by a machine (e.g., a computer). Forexample, a machine-readable (e.g., computer-readable) medium includes amachine (e.g., a computer) readable storage medium such as a read onlymemory (“ROM”), random access memory (“RAM”), magnetic disk storagemedia, optical storage media, flash memory devices, etc.

In the foregoing specification, implementations of the disclosure havebeen described with reference to specific example implementationsthereof. It will be evident that various modifications can be madethereto without departing from the broader spirit and scope ofimplementations of the disclosure as set forth in the following claims.The specification and drawings are, accordingly, to be regarded in anillustrative sense rather than a restrictive sense.

What is claimed is:
 1. A method comprising: identifying, by a processingdevice, a temperature related to a memory device of a plurality ofmemory devices; determining, whether the temperature related to thememory device satisfies a threshold temperature condition; responsive todetecting that the temperature related to the memory device satisfiesthe threshold temperature condition, identifying an entry associatedwith the memory device from a plurality of entries in a data structure,wherein each entry of the plurality of entries corresponds to one of theplurality of memory devices; determining a parameter value associatedwith the memory device from the entry, wherein the parameter value isfor a programming operation to store data at the memory device;adjusting the parameter value associated with the memory device togenerate an adjusted parameter value; and storing the adjusted parametervalue in the entry of the data structure.
 2. The method of claim 1,wherein adjusting of the parameter value associated with the memorydevice further comprises: updating a programming step size of theprogramming operation from a first value to a second value, wherein theprogramming step size indicates an increase in a voltage applied at thememory device to store data at the memory device.
 3. The method of claim2, wherein updating the programming step size further comprisesadjusting a first voltage of a first programming pulse to a secondvoltage of a second programming pulse of the programming operation. 4.The method of claim 1, further comprising determining an error rateassociated with the memory device, wherein adjusting the parameter valueis based on the error rate of the memory device satisfying a thresholderror rate.
 5. The method of claim 1 further comprising: determiningthat the temperature related to the memory device satisfies thethreshold temperature condition when the temperature is below athreshold temperature, wherein adjusting the parameter value correspondsto a decrease in a voltage step associated with the programmingoperation.
 6. The method of claim 1 further comprising: determining thatthe temperature related to the memory device satisfies the thresholdtemperature condition when the temperature is above a thresholdtemperature, wherein adjusting the parameter value corresponds to anincrease in a voltage step associated with the programming operation. 7.The method of claim 1, wherein the data structure comprises a table forstoring data related to the plurality of the memory device.
 8. A systemcomprising: a plurality of memory devices; and a processing device,operatively coupled with the plurality of memory devices, to performoperations comprising: identifying a temperature related to a memorydevice of the plurality of memory devices; determining, whether thetemperature related to the memory device satisfies a thresholdtemperature condition; responsive to detecting that the temperaturerelated to the memory device satisfies the threshold temperaturecondition, identifying an entry associated with the memory device from aplurality of entries in a data structure, wherein each entry of theplurality of entries corresponds to one of the plurality of memorydevices; determining a parameter value associated with the memory devicefrom the entry, wherein the parameter value is for a programmingoperation to store data at the memory device; adjusting the parametervalue associated with the memory device to generate an adjustedparameter value; and storing the adjusted parameter value in the entryof the data structure.
 9. The system of claim 8, wherein adjusting ofthe parameter value associated with the memory device further comprises:updating a programming step size of the programming operation from afirst value to a second value, wherein the programming step sizeindicates an increase in a voltage applied at the memory device to storedata at the memory device.
 10. The system of claim 9, wherein updatingthe programming step size further comprises adjusting a first voltage ofa first programming pulse to a second voltage of a second programmingpulse of the programming operation.
 11. The system of claim 8, whereinthe processing device is to perform further operations comprising:determining that the temperature related to the memory device satisfiesthe threshold temperature condition when the temperature is below athreshold temperature, wherein adjusting the parameter value correspondsto a decrease in a voltage step associated with the programmingoperation.
 12. The system of claim 8, wherein the processing device isto perform further operations comprising: determining that thetemperature related to the memory device satisfies the thresholdtemperature condition when the temperature is above a thresholdtemperature, wherein adjusting the parameter value corresponds to anincrease in a voltage step associated with the programming operation.13. The system of claim 8, wherein the data structure comprises a tablefor storing data related to the plurality of the memory device.
 14. Anon-transitory computer readable storage medium storing instructions,which when executed by a processing device, cause the processing deviceto perform operations comprising: identifying a temperature related to amemory device of the plurality of memory devices; determining, whetherthe temperature related to the memory device satisfies a thresholdtemperature condition; responsive to detecting that the temperaturerelated to the memory device satisfies the threshold temperaturecondition, identifying an entry associated with the memory device from aplurality of entries in a data structure, wherein each entry of theplurality of entries corresponds to one of the plurality of memorydevices; determining a parameter value associated with the memory devicefrom the entry, wherein the parameter value is for a programmingoperation to store data at the memory device; adjusting the parametervalue associated with the memory device to generate an adjustedparameter value; and storing the adjusted parameter value in the entryof the data structure.
 15. The non-transitory computer readable storagemedium of claim 14, wherein the processing device is to perform furtheroperations comprising: determining that the temperature related to thememory device satisfies the threshold temperature condition when thetemperature is below a threshold temperature, wherein adjusting theparameter value corresponds to a decrease in a voltage step associatedwith the programming operation.
 16. The non-transitory computer readablestorage medium of claim 14, wherein the processing device is to performfurther operations comprising: determining that the temperature relatedto the memory device satisfies the threshold temperature condition whenthe temperature is above a threshold temperature, wherein adjusting theparameter value corresponds to an increase in a voltage step associatedwith the programming operation.
 17. The non-transitory computer readablestorage medium of claim 14, wherein the processing device is to performfurther operations comprising: determining an error rate associated withthe memory device, wherein adjusting the parameter value is based on theerror rate of the memory device satisfying a threshold error rate. 18.The non-transitory computer readable storage medium of claim 14, whereinadjusting of the parameter value associated with the memory devicefurther comprises: updating a programming step size of the programmingoperation from a first value to a second value, wherein the programmingstep size indicates an increase in a voltage applied at the memorydevice to store data at the memory device.
 19. The non-transitorycomputer readable storage medium of claim 18, wherein updating theprogramming step size further comprises adjusting a first voltage of afirst programming pulse to a second voltage of a second programmingpulse of the programming operation.
 20. The non-transitory computerreadable storage medium of claim 14, wherein the memory device comprisesa plurality of multi-level cells (MLCs).